This invention is related, in general, to signal conversion and, more specifically, to signal conversion using a double balanced mixer circuit.
It is common in a transceiver circuit that the received signal be down-converted in frequency from the Radio Frequency (RF) range to the Intermediate Frequency (IF) range. The transceiver in a cellular phone employs a mixer circuit that typically receives both the RF input signal from an antenna and a locally generated oscillator signal. The mixer generates an output signal having a frequency that is the difference between the frequency of the RF signal and the frequency of the oscillator signal, thus mixing the frequency of the received signal down to the IF frequency range.
A cost-effective mixer is needed having a lower noise FIGURE and a higher third order intermodulation product (IP3) to improve the sensitivity of phones.